Hello, can someone please help me clarify these 2 things. The Take-off ref page has 2 entries that I am still not sure about. The Ref OAT on page 2, (I don't mean the Reduced Thrust entry on page 1) I read somewhere that this is used as a reference for the actual outside air temperature. This value would be more accurate than the OAT indicated on the EICAS since that value is subject to errors on the ground. Is this correct? So no entry is required here for your take-off numbers? Also The Runway Position entry on take-off ref page 1, Is the value entered here how many feet down the runway you plan to engage the A/T and used to automatically update FMC position during the take-off roll? Or is it for an intersection take-off? if so can someone clarify how this works and how would you enter this amount with the + or

No entry is required in the REF OAT field. (Required entries are always "boxes". Possible entries are dashes. I'm not even sure if it's possible to enter another temperature as REF OAT.)The short answer for question 2 is that it isn't modelled in PIC, so why bother?Longer answer: Yes, it's used for an intersection takeoff, and you enter the distance between the runway threshold and the intersection you are going to use. It's entered either in feet or meters, and the distances are shown on airport charts.And yes, it is the distance from the runway threshold where you plan to press the N1/EPR button to update the FMC position. But you wouldn't enter anything unless you plan to take off from an intersection. It's not "uh, I think I'll, uh, press N1 when we've rolled 1500 down the runway". :-)I'm not sure, but the distance entered might also be used to calculate takeoff performance.Martin767 fetishistIt's a lot like life and that's what's appealing

If using an intersection T/O then the distance is needed to calculate the avail performance, as you may need a higher flap setting due having less available runway.

So in reference to the Runway Position field how does the + or - apply, If the runway is 10,000 FT and you are taking off at an intersection that is 2000ft down the runway would you enter + or - 2000? I just don

You would enter -2000, because you are SUBTRACTING 2000ft from the overall length of the runway...makes sense, doesn't it? As for always starting takeoff run from the beginning of the runway, that is obviously the norm but is not done 100% of the time I'm sure.Ryan

It's basically the PIC's call. Runway behind you is one of the three most useless things in aviation.Lee Hetherington (KBED)

"This value would be more accurate than the OAT indicated on the EICAS since that value is subject to errors on the ground. Is this correct?"The EICAS TAT reading should be relatively accurate on the ground as long as you have pneumatics available, November. Ground/APU/Engine Bleed air is piped to the TAT probe on the nose (a few feet below the captain's window on the left hand side)... noting here that by the time it reaches the TAT probe, it has cooled (and won't burn you)... and the air rushing through the probe creates a venturi effect (negative pressure). This negative air pressure draws ambient air into the TAT probe and over the temperature sensing elements so that the TAT probe gives a proper reading even though the aircraft is not moving. You can hear the hissing of the bleed air rushing out of the TAT probe when you walk past the nose (not to be confused with air leaking out of the tyres ;-))."So no entry is required here for your take-off numbers? Also The Runway Position entry on take-off ref page 1, Is the value entered here how many feet down the runway you plan to engage the A/T and used to automatically update FMC position during the take-off roll? Or is it for an intersection take-off? if so can someone clarify how this works and how would you enter this amount with the + or

>>The entry is counter-intuitive. "+" is used for a short runway, "-" for a longer runway Ok so let me make sure. Lets say a runway is 11,000 Ft long and the tower instructs me to take off at an intersection 1000Ft down the runway I would enter this as +1000? Thank You

>This value is used _only_ for position updating.Are you sure about this Ian?From the AOM:"Entry of a value after takeoff speeds are selected removes the speeds and displaysthe scratchpad message TAKEOFF SPEEDS DELETED."Why would the takeoff speeds be deleted unless the position shift entry has some effect on the takeoff speed calculations?Martin767 fetishistIt's a lot like life and that's what's appealing

Hi,Let me try to shed some light or maybe even more blur the issue :-badteeth Here is what 747 AOM says:****************************POS SHIFT Displays the selected takeoff runway and TO/GA

>Runway behind you is one of the three most useless things in aviationLOL... And what's the other two? Please excuse an ignorant PIC-user. ;-)Regards,

>Valid entries are X, XX in + or - hundreds of meters(3 or 03 is 300 meters beyond the runway threshold; -3 or -03 is 300 meters prior to runway threshold).I think the FMC in PIC only accepts entries in feet. Is it like that in the real 767?Ok so correct me if I am wrong :-) If the Runway is 11000 Ft and I am taking off at an intersection 2000Ft down the runway I would enter +2000. When taking of from a runway with a displaced threshold 1500Ft down the runway I would enter -1500 to start at the very beginning for takeoff. Thank You

One is "fuel on the ground"I think the other one is "altitude above you" or words to that effect.Rob.

>I think the FMC in PIC only accepts entries in feet. Is it>like that in the real 767?No no, it depends on the airline option of course. :-) Why would a plane with everything else metric have this entry in feet?Also, on some planes the entry is in hundreds of meters (i.e. possible entries are 300 to -300 = 3000 to -3000 m), and on others the entry is in meters (i.e. possible entries are 3000 to -3000).>Ok so correct me if I am wrong :-) If the Runway is 11000 Ft>and I am taking off at an intersection 2000Ft down the runway>I would enter +2000. When taking of from a runway with a>displaced threshold 1500Ft down the runway I would enter -1500>to start at the very beginning for takeoff. Thank YouSounds like you're right.Martin767 fetishistIt's a lot like life and that's what's appealing

I remember it as "air in your fuel tanks".Lee Hetherington (KBED)